What do I need to purchase…? The ATMEGA168 regular or the one with the arduino boot?
[ATmega168 with Arduino Bootloader or [ATmega328 with Arduino Bootloader depending on how new/old your Arduino is.](http://www.sparkfun.com/commerce/product_info.php?products_id=9217)](ATmega168 with Arduino Bootloader - DEV-08846 - SparkFun Electronics)